In recent years, technology for providing multiple information signal layers has been widely adopted in the field of optical recording media in order to further increase the recording capacity. Information signal layers of a multilayer optical recording medium other than the farthest information signal layer from the medium surface are required to have a high transmittance and a small transmittance change before and after recording.
In the field of multilayer optical recording media, various film configurations have been studied with regard to information signal layers other than the farthest information signal layer from a medium surface. For example, Patent Document 1 proposes a film configuration in which a protective layer (dielectric layer) mainly containing indium oxide and tin oxide is provided on at least one side of a transmissive recording layer.